Re: st: RE: sum of rows in stata matrix

[Nick Cox <njcoxstata@gmail.com>]

In addition, you could read that matrix into Mata, calculate row sums
and then push back the result. That may sound more work than it is, as
it is just one line.

. matrix A = (1,2,9\2,7,5\2,4,18)

. mata : st_matrix("B", rowsum(st_matrix("A")))

. mat li B

B[3,1]
    c1
r1  12
r2  14
r3  24

Alternatively, various add-ons were published by users between 1997
and 2000. Although it's a better strategy to work in Mata, these
commands will work if installed. -matfunc- includes a -matsum-
command.

STB-39  dm49  . . . . . . . . . . . . . . . . . . . . Some new matrix commands
        (help matfunc, varfunc if installed)  . . . . . . . . . . .  J. Weesie
        9/97    pp.17--20; STB Reprints Vol 7, pp.43--48
        collection of new matrix commands; several for explicit matrices
        and a few for implicit matrices (i.e., variables)
        see mata matrix language incorporated into Stata 9

STB-50  dm69  . . . . . . . . . . . . . . . . . .  Further new matrix commands
        (help matdelrc, matewm, matmad, matpow if installed)  . . .  N. J. Cox
        7/99    pp.5--9; STB Reprints Vol 9, pp.29--34
        collection of new matrix commands providing additional matrix
        checking, management, element-wise operators, maximum absolute
        difference, and power

STB-56  dm79  . . . . . . . . . . . . . . . . . . Yet more new matrix commands
        (help matcorr, matewmf, matvsort, svmat2 if installed)  . .  N. J. Cox
        7/00    pp.4--8; STB Reprints Vol 10, pp.17--23
        commands to produce a correlation matrix, elementwise monadic
        function of another matrix, selected subsets of matrix rows
        and columns, vec or vech of a matrix, elements sorted within
        a vector, matrix from a vector, and commands to save matrices
        see mata matrix language incorporated into Stata 9.0

Nick
njcoxstata@gmail.com


On 7 October 2013 05:18, Kieran McCaul <kieran.mccaul@uwa.edu.au> wrote:

> matrix A = (1,2,9\2,7,5\2,4,18)
> matrix list A
>
> * This sums across rows of A
> matrix X1 = J(3,1,1)
> matrix list X1
>
> matrix B1 = A*X1
>
> matrix list B1
>
> *This sums down columns of A
> matrix X2 = J(1,3,1)
> matrix list X2
>
> matrix B2 = X2*A
>
> matrix list B2

Shuaizhang Feng

> Suppose I have a matrix A in stata and I want to calculate sum of rows
> for each column. What would the most simple way to do it? thanks.
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